The present invention is directed to a spray gun for delivering a compressible fluid from a discharge opening in the spray gun. The invention is also directed to a number of attachments that can be positioned on the spray gun to allow the spray gun to be utilized for different purposes.
Spray guns have been used in the prior art for dispensing different materials. Normally the spray guns are connected to a source of compressed air, such as a compressor, and the compressed air is used to dispense a material. Spray guns have normally contained a movable valve that is used to control the flow of compressed air through the spray gun. The compressed air generally moves through a discharge nozzle located on the spray gun and as the compressed air moves through the discharge nozzle it dispenses the material being handled by the spray gun. The material being dispensed by the spray gun is normally supplied to the spray gun in the region of the discharge nozzle.
Prior art spray guns are normally designed for a particular end use; such as spray painting. Different nozzles may be supplied with the spray gun for varying the pattern in which the material is dispensed from the spray gun but these different nozzles do not alter the basic purpose for which the spray gun was constructed.
Prior art spray guns have a needle valve located in the paint supply passageway for providing positive control to the supply of paint to the spray gun. The needle valve is displaced by the displacement of the trigger on the spray gun. The displacement of the needle valve allows paint to flow to the discharge end of the spray gun. When the trigger is released the needle valve is biased to cause the valve to close and shut off the flow of paint to the spray gun. The needle valve and trigger are arranged so that when the trigger is displaced air flows to the spray gun before the needle valve is displaced to allow paint to flow to the discharge end of the spray gun. When the trigger is released the needle valve closes and shuts off the flow of paint to the spray gun before the air flowing to the spray gun is shut off. The needle valve to control the paint supply and the operational sequence for the needle valve have been thought necessary to produce an acceptable spray pattern for a spray gun.
The prior art spray guns also do not have good controls for the supply of compressed air to the spray gun. When the trigger mechanism is displaced the compressed air is supplied to the gun until the trigger mechanism is released and the supply of compressed air is shut off. There is usually no provision in the trigger mechanism to regulate the supply of compressed air. Instead the trigger mechanism just provides an on-off type of control for the supply of compressed air to the spray gun.
There is a need for a spray gun that can be adapted for a number of end uses. Principally there is a need for a spray gun that will accept various attachments or nozzles that will allow the end use of the spray gun to be varied. In particular it is desirable to have a spray gun that is capable of discharging gases, liquids or particulate solids. In addition, there is a need for a spray gun that does not require a needle valve in the paint supply passageway to provide positive control for the supply of paint to the spray gun. Further it is desirable to have a spray gun where the supply of compressed air to the spray gun can be regulated.